Knife bar stop



March 16, 1965 w, c R 3,173,327

' KNIFE BAR STOP Filed Feb. 9, 1962 IN V EN TOR. WILLIAM C. RUPP OM01, "My; [lowly ATTORNEYS United States Patent Ohio Filed Feb. 9, 1962, Set. N 172,126 4 Claims. (Ql. 83-588) This invention relates as indicated to a novel knife bar stop, and more particularly to a safety stop designed to be incorporated in a hydraulic paper cutting machine which may, for example, be of the type illustrated and described in my prior co-pending application Serial No. 862,841, filed December 30, 1959, now Patent No. 3,- 111,876 for Automatic Gauge for Paper Cutting Machines and the Like.

In the usual hydraulic paper cutting machine, the knife bar and knife are adapted to be reciprocated in vertical ways to make the out after a binder clam-p has likewise been brought down firmly to clamp a stack of sheets upon the table of the machine. When the knife is returned to uppermost position following the making of the cut, the binder clamp is likewise returned to uppermost position and in such position will still project downwardly slightly below the cutting edge of the knife. This permits the operator to adjust the Work upon the table of the machine without danger of cutting the backs of his hands as he reaches beneath the knife and clamp inasmuch as the cutting edge of the knife blade will be closely against the forward surface of the binder clamp as well as slightly above the lower surface thereof.

Unfortunately, in the usual hydraulic paper cutting machine, slight leakage of fluid within the hydraulic system may have the result of permitting the knife to descend slightly during periods of non-use of the machine, as over a Weekend for example, so that when an operator next makes use of the machine the cutting edge of the knife may have descended below the under surface of the binder clamp and thus be capable of inflicting serious injury to the operator, particularly during setup. It is accordingly a principal object of this invention to provide a modified hydraulic paper cutting machine, and more particularly a novel knife bar stop therefor which will afford assurance that the knife bar and knife will not thus descend during periods of non-use of the machine to catch the operator unawares.

Another object of this invention is to provide such knife bar stop which may be readily incorporated in existing hydraulic paper cutting machines in the field.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various Ways in which the principle of the invention may be employed.

The drawing shows a front elevational view of a paper cutting machine of the type illustrated and described in detail in my aforesaid co-pending application Serial No. 862,841, to which reference may be made for certain particulars including my novel knife bar stop. Reference may also be had to my prior Patent 2,781,093.

Referring now to such drawing, the machine there illustrated comprises the usual side frame members 1 and 2 interconnected by lower crossbrace 3 and upper frame or head member 4. A horizontal table 5 is carried between such side frame members and is adapted to support a stack of sheets for positioning thereon. A

back gauge 6 may be adjusted forwardly or rearwardly along table 5 by means of hand wheel 7 and side gauges such as 8 are provided for lateral positioning of the stack. A pointer 9 is provided to indicate the exact position of such back gauge on an endless steel tape attached to the latter, and a shaded lamp 1t illuminates the work upon the table.

The lower portion of the binder clamp 11 appears behind knife 12 which is carried by knife bar 13 supported for downward swinging slicing action by links 14 and 15 pivotally secured to head frame member 4. Fluid pressure cylinder 16 is pivotally mounted at its lower end on bracket 17 on side frame member 2 and its upwardly projecting rod 18 is pivotally connected to the outwardly projecting end of link 15. Accordingly, reciprocation of piston rod 18 serves to lower and raise the knife with a slicing action to cut a stack of sheets positioned on table 5 against back gauge 6 and one of the side gauges such as 8.

A pump P is mounted on cross-frame member 3 beneath table 5 and projecting through side member 1. It is driven by an electric motor M and is operative to deliver hydraulic fluid under pressure from a sump to control valve 19. A relief valve (not shown) is operative to return the pump delivery to the sump should the control valve or other part of the fluid pressure system become blocked.

To initiate operation of the machine, the operator moves safety lever 20 with his left hand to free operating lever 21 which he thereupon rocks with his right hand to rock lever 22 (through link 23) keyed to shaft 24, thereby in turn rocking the valve spool control lever 25 about the axis of shaft 24. The spool of valve 19 is accordingly shifted to admit fluid under pressure to the lower end of the binder clamp cylinder (not shown) which operates to bring the binder clamp down into clamping engagement with the stack of sheets on table 5. When the binder clamp is all the way down on the stack and pressing firmly thereupon with a predetermined pressure, the back pressure built up in the line is utilized to actuate valve means (not shown) to direct fluid under pressure to line 26 leading to the upper end of knife cylinder 16, thereby to move piston rod 18 downwardly and thus bring down knife 12 to make the cut. The lower end of cylinder 16 is relieved through line 27, permitting return flow to sump.

As soon as the cut is thus made, the operator shifts valve 19 to admit fluid under pressure to line 27 and thereby to the lower end of knife cylinder 16 and also to admit fluid under pressure to the upper end of the clamp cylinder to raise the knife to the position indicated in the drawing and also to raise the binder clamp to the position there illustrated slightly beneath the lower cutting edge of such knife.

A laterally rigid two-piece telescopic tubular link 28 is pivotally connected at 29 to the lower end of bracket 30 secured to side frame member 2 of the machine, and the upper end of such link is pivotally connected to the lower outwardly projecting end of knife bar link 15 at the same horizontal pivot 31 as the upper end of piston rod 18. A compression spring 32 encircles longitudinally telescopic link 28 and serves to exert an upward force on knife bar link 15 sufficient to maintain the latter in uppermost position in the absence of fluid pressure tending actively to force rod 18 downwardly in cylinder 16. Consequently, and despite appreciable fluid leakage in the hydraulic system, the knife bar and stop will be maintained in uppermost position except when intentionally brought down to make a cut, and the cutting edge of the knife will be protected by the binder clamp.

While the force of the compression spring must, of

course, be overcome by the hydraulic piston-cylinder ass m y hen mak a u 1 1 fq i i Q i n es quential in comparison to that ordinarily thus exerted when cutting a stack of sheets on the table of the machine. When .the machine is at rest with the knife in elevated position, the link 28 will be inclined at about 30 to the vertical and will xtend in a direction generally normal to parallel 14 ahd 15,- thus being in the most effective position for the intendedpurpose. While the force of the Spring must, of course, heoyercome as above indicated When making a out, such spring nevertheless assists in returning the knife to uppermostrposition and is capable of m ntaining the latter in such position yen whenthe fluid pressure system is devoid of fluid during overhaul, for example. The device is relatively simple, and inexpensive and adapted .to be installedon a variety of hydraulic paper cutting machines of the general type illustrated and described above, his also simple andfoolproof in operatron and does not require highly precise adjustment such as is the case when utilizing mechanical latches, or the like for a similar pnrpose. The pivotal connections of the knife links, cylinder, and telescopic link are, of course, all parallel and normal to the plane of the knife. While such tclescopiclink is generally normal to the knife links when the knife is in fully elevated position so that the ,compressionspring is of maxirnumeffectiveness, it will be seen that as the knife is brought down through operation of the pistojn cylinder assembly with r esultant further cornpressio'n ofthe spring, such spring becomes less and less eifectivelydisposed to exert up ward rocking force upon the knife link on which it bears. i V i .Other modes of applying the principle of theinv t i may be employed, change being made as regards the details described, provided the features stated in any of the following claims or theequivalentof such be employed.

I therefoieparticularly point out distinctly claim as my'invention: i l 7 l. ,Ina paper euaing machine havinga frame, a table wavere 'li' b'y, a-b ad cl mp a ap e t m ,Work

as saidtable, a knife mounted forj down-and-up movement insaid frame towardand awaylfro rn the u pper surfaoe of saidtabjlqan overhead portion of said fra'me above 'saidtable, a pairiofparallel links pivotally connected to said knife and said overhead portion of said frame to impart a lateral slicingaction to such movement" of said knife, and a fluidpressure cylinder pivotallyinounted on said frame having an upwardly ex'tending roid pivotally connected to one said linkand thereby effective when reciprocated likewise toreciprocate said knife; a laterally rigid longitudinally telescopic link pivotally connected at itsloyver end to said frame and pivotally connected at its upper end to said one link at the same, point of connection as said rod, all said pivotslof said cylinder, rod, and telescopic link being parallel to one another and normal to the plane of said knife, saidtelescopic link being mounted generally normal to said one link connected to said knife when the latter isin fully elevated positionand also to assist somewhat in returning the kjnife touppermost position after making a cut, and acompression spring encircling said telescopic link of sufiicient strength normally to hold said knife in fully elevated position, said fluid pressure cylinder, however, being powerful enough to overcome the force ofsaidspring to bring down theknife to make the cut.

2. The machine of. claim 1, wherein said clamp in fully elevated position normally projects slightly below said knife in its fully elevated position, and the cutting edge of said knife lies closely against said clamp. i i

a paper cutting machine having a frame, a table supported thereby, a binder clamp adapted to clamp work on said table, a'knife mounted for down-and-up movement in said frame toward and away from the upper surface of said table, an overhead portion of said frame above said table, a pair of parallel links pivotally connected to said knife and said overhead portion of said frame to impart avlateral slicing action to such movement of said knife, and a fluid pressure cylinder pivotally mounted on said frame having an upwardlyextending rod pivotally connected to one said link and thereby effective when reciprocated likewise to reciprocate said knife; a laterally rigid longitudinally telescopic link pivotally connected at its lower end to said frame and pivotally connected at its upper end to said one link at the same point ,of connection as said rod, all said pivots of said cylinder, rod, and telescopic link being parallel to one another and normal to the plane of said knife, and a compression spring encircling said telescopic link of suflicient strength normally to hold said knife in fully elevated position and also to assist somewhat in returning the knife to uppermost position after making a cut, said fluid pressure cylinder, however, being powerful enough to overcome the force of said spring to bring down the knife to make the cut.

4. In a paper cutting machine having a frame, a table supported thereby, a binder clamp adapted to clamp work on said table, a knife mounted for down-and-up movement in said frame toward and away from the upper surface of said table, an overhead portion of said frame above said table, a pair of parallel links pivotally connected to said knife and said overhead portion of said frame to impart a lateral slicing action to such movement of said knife, and a fluid pressure cylinder pivotally mounted on said frame having an upwardly extending rod pivotally connected to an extension of one said linkbeyond the point of pivotal connection of said knife to said link and thereby effective when re'ciprocated likewise to reciprocate said knife; a laterally rigid longitudinally telescopic link pivotally connected at its lower end to saidframe and pivotally connected at its upper end to said one link at the same point of connection as said rod, all said pivots ofsaid Cylinder, rod, and .telescopiclink being parallel to one another and normal totheplane of said knife, said telescopic link being mounted generallynorrnal to said one link connected to said knifewhen the latter is in fully elevated position, and acompression spring encircling said telescopic link of sufiicient strength normally to hold said knife in fully elevated position, said fluid pressure cylinder, however, being powerful enough to overcome the force of said spring to bring down the knife tomake the cut, and said telescopic link and spring being more nearly aligned with the point of pivotal connection of said one link to said overhead portion of said frame.

FOREIGN v PATENTS 695,469 8/53 Great Britain.

ANDREW R. JU HASZ, Primary Examiner.

EDWARD C. ALLEN, Examiner, 

1. IN A PAPER CUTTING MACHINE HAVING A FRAME, A TABLE SUPPORTING THEREBY, A BINDER CLAMP ADAPTED TO CLAMP WORK ON SAID TABLE, A KNIFE MOUNTED FOR DOWN-AND-UP MOVEMENT IN SAID FRAME TOWARD AND AWAY FROM THE UPPER SURFACE OF SAID TABLE, AN OVERHEAD PORTION OF SAID FRAME ABOVE SAID TABLE, A PAIR OF PARALLEL LINKS PIVOTALLY CONNECTED TO SAID KNIFE AND SAID OVERHEAD PORTION OF SAID FIRST TO IMPART A LATERAL SLICING ACTION TO SUCH MOVEMENT OF SAID KNIFE, AND A FLUID PRESSURE CYLINDER PIVOTALLY MOUNTED ON SAID FRAME HAVING AN UPWARDLY EXTENDING ROD PIVOTALLY CONNECTD TO ONE SAID LINK AND THEREBY EFFECTIVE WHEN RECIPROCATED LIKEWISE TO RECIPROCATE SAID KNIFE; A LATERALLY RIGID LONGITUDINALLY TELESCOPIC LINK PIVOTALLY CONNECTED AT ITS LOWER END TO SAID FRAME AND PIVOTALLY CONNECTED AT ITS UPPER END TO SAID ONE LINK AT THE SAME POINT OF CONNECTION AS SAID ROD, ALL SAID PIVOTS OF SAID CYLINDER, ROD, AND TELESCOPE LINK BEING PARALLE TO ONE ANOTHER AND NORMAL TO 